That's the opposite of how PPP usually works. Purchasing Power Parity means that although you earn much less in China, things also cost less, so your cost of living and relative wealth are the same.
So PPP usually is a boost to the poorer countries. The post you're responding to claims that this is less and less relevant because the things they want to buy are global in nature. The fact that these things cost more actually reinforces that point.
You often are better off in poorer countries anyway even if some goods cost more. My coworkers in India have servants that clean their house every day - I make more $$ than them by a bit but I could not afford that and so I personally have to spend a few hours in cleaning every week and my house isn't as clean (because I'm spending less time cleaning)
Better off than no job. But it will be interesting seeing culture shock of a few generations in some countries that seem to be improving fast and thus the servants kids can get better jobs. I hope it works out that way anyway.
So PPP usually is a boost to the poorer countries. The post you're responding to claims that this is less and less relevant because the things they want to buy are global in nature. The fact that these things cost more actually reinforces that point.